Experimental Study on Vertical Fire Spread of Thin Hanging Combustibles

AbstractIn order to study vertical fire spread law of thin combustibles hang in atrium, the vertical combustion characteristics of thin combustibles was tested using vertical combustion experimental equipment, limited oxygen index tester and calorific value analyzer. Combustion parameters such as oxygen index, calorific value, vertical fire spread rate, surface temperature, mass loss rate and heat release rate were obtained. Fitting line showed that vertical fire spread rate, mass loss rate and heat release rate can be expressed as a power function of burning time. Vertical fire spread was accelerated growth, which the fire spread rate is over ten times of horizontal fire spread rate. The maximum surface temperature of the combustion cotton was about 500°C, the maximum surface temperature of the combustion cardboard was about 700°C. Experimental results showed that the thin combustibles hang in atrium and other large spaces have a greater fire risk, its vertical fire spread is very fast, so fire prevention measures should be taken in practical applications

(E)-3-Allyl­sulfanyl-N-(4-methoxy­benzyl­idene)-5-(3,4,5-trimethoxy­phen­yl)-4H-1,2,4-triazol-4-amine

The title compound, C22H24N4O4S, adopts a trans configuration with respect to the C=N double bond. A weak intra­molecular C—H⋯N hydrogen bond is observed between the N atom of the C=N double bond and its neighboring phenyl H atom. The crystal structure is stabilized by inter­molecular C—H⋯N hydrogen bonds and C—H⋯π inter­actions

N-[(E)-2-Chloro­benzyl­idene]-3-(4-methyl­benzyl­sulfan­yl)-5-(3,4,5-trimethoxy­phen­yl)-4H-1,2,4-triazol-4-amine

In the title compound, C26H25ClN4O3S, the acyclic imine group exhibits an E configuration. The triazole ring is oriented at dihedral angles of 53.84 (2), 70.77 (1) and 32.59 (3)° with respect to the benzene rings of the 2-chloro­benzyl­idene, 4-methyl­benzyl­sulfanyl and 3,4,5-trimethoxy­phenyl groups, respectively. The crystal packing is stabilized by weak inter­molecular C—H⋯N, C—H⋯S and C—H⋯π inter­actions

Electrically-controllable RKKY interaction in semiconductor quantum wires

We demonstrate in theory that it is possible to all-electrically manipulate the RKKY interaction in a quasi-one-dimensional electron gas embedded in a semiconductor heterostructure, in the presence of Rashba and Dresselhaus spin-orbit interaction. In an undoped semiconductor quantum wire where intermediate excitations are gapped, the interaction becomes the short-ranged Bloembergen-Rowland super-exchange interaction. Owing to the interplay of different types of spin-orbit interaction, the interaction can be controlled to realize various spin models, e.g., isotropic and anisotropic Heisenberg-like models, Ising-like models with additional Dzyaloshinsky-Moriya terms, by tuning the external electric field and designing the crystallographic directions. Such controllable interaction forms a basis for quantum computing with localized spins and quantum matters in spin lattices.Comment: 5 pages, 1 figur

(Z)-Methyl 4-(1,3-benzothia­zol-2-yl­sulfan­yl)-2-(methoxy­imino)-3-oxo­butanoate

In the mol­ecular structure of the title compound, C13H12N2O4S2, there is a dihedral angle of 0.41 (13)° between the benzene and thia­zole rings. In the crystal, inversion dimers linked by two C—H⋯O inter­actions together with π–π stacking between the parallel benzene rings of adjacent mol­ecules [centroid–centroid distance = 3.673 (2) Å]

Summertime CO2 fluxes from tundra of Ny-Ålesund in the High Arctic

The Arctic ecosystem, especially High Arctic tundra, plays a unique role in the global carbon cycle because of amplified warming in the region. However, relatively little research has been conducted in High Arctic tundra compared with other global ecosystems. In the present work, summertime net ecosystem exchange (NEE), ecosystem respiration (ER), and photosynthesis were investigated at six tundra sites (DM1–DM6) on Ny-Ålesund in the High Arctic. NEE at the tundra sites varied between a weak sink and strong source (−3.3 to 19.0 mg CO2·m−2·h−1). ER and gross photosynthesis were 42.8 to 92.9 mg CO2·m−2·h−1 and 54.7 to 108.7 mg CO2·m−2·h−1, respectively. The NEE variations showed a significant correlation with photosynthesis rates, whereas no significant correlation was found with ecosystem respiration, indicating that NEE variations across the region were controlled by differences in net uptake of CO2 owing to photosynthesis, rather than by variations in ER. A Q10 value of 1.80 indicated weak temperature sensitivity of tundra ER and its response to future global warming. NEE and gross photosynthesis also showed relatively strong correlations with C/N ratio. The tundra ER, NEE, and gross photosynthesis showed variations over slightly waterlogged wetland tundra, mesic and dry tundra. Overall, soil temperature, nutrients and moisture can be key effects on CO2 fluxes, ecosystem respiration, and NEE in the High Arctic

Long-term nitrogen fertilization decreased the abundance of inorganic phosphate solubilizing bacteria in an alkaline soil

Inorganic phosphate solubilizing bacteria (iPSB) are essential to facilitate phosphorus (P) mobilization in alkaline soil, however, the phylogenetic structure of iPSB communities remains poorly characterized. Thus, we use a reference iPSB database to analyze the distribution of iPSB communities based on 16S rRNA gene illumina sequencing. Additionally, a noval pqqC primer was developed to quantify iPSB abundance. In our study, an alkaline soil with 27-year fertilization treatment was selected. The percentage of iPSB was 1.10 similar to 2.87% per sample, and the dominant iPSB genera were closely related to Arthrobacter, Bacillus, Brevibacterium and Streptomyces. Long-term P fertilization had no significant effect on the abundance of iPSB communities. Rather than P and potassium (K) additions, long-term nitrogen (N) fertilization decreased the iPSB abundance, which was validated by reduced relative abundance of pqqC gene (pqqC/16S). The decreased iPSB abundance was strongly related to pH decline and total N increase, revealing that the long-term N additions may cause pH decline and subsequent P releases relatively decreasing the demands of the iPSB community. The methodology and understanding obtained here provides insights into the ecology of inorganic P solubilizers and how to manipulate for better P use efficiency

Exercise Training Attenuates Proinflammatory Cytokines, Oxidative Stress and Modulates Neurotransmitters in the Rostral Ventrolateral Medulla of Salt-Induced Hypertensive Rats

Background/Aims: Exercise training (ExT) was associated with cardiovascular diseases including hypertension. The rostral ventrolateral medulla (RVLM) is a key region for central control of blood pressure and sympathetic nerve activity. Therefore, this study aimed to investigate the mechanisms within RVLM that can influence exercise training induced effects in salt-induced hypertension. Methods: Male Wistar rats were fed with a normal salt (0.3%) (NS) or a high salt (8%) (HS) diet for 12 weeks to induce hypertension. Then these rats were given moderate-intensity ExT for a period of 12 weeks. RVLM was used to determine glutamate and gamma-aminobutyric acid (HPLC), phosphorylated IKKβ, Fra-LI, 67-kDa isoform of glutamate decarboxylase (GAD67), proinflammatory cytokines (PIC) and NADPH-oxidase (NOX) subunits expression (Immunohistochemistry and Immunofluorescence, Western blotting). PIC and NF-κB p65 activity in the plasma were evaluated by ELISA studies. Renal sympathetic nerve activity (RSNA) was recorded and analyzed using the PowerLab system. Results: High salt diet resulted in increased mean arterial pressure and cardiac hypertrophy. These high salt diet rats had higher RVLM levels of glutamate, PIC, phosphorylated IKKβ, NF-κB p65 activity, Fra-LI, superoxide, NOX-2 (gp91phox) and 4, and lower RVLM levels of gamma-aminobutyric acid and GAD67, and higher plasma levels of PIC, norepinephrine, and higher RSNA. ExT attenuated these changes in salt-induced hypertensive rats. Conclusions: These findings suggest that high salt diet increases the activity of NF-κB and the levels of PIC and oxidative stress, and induces an imbalance between excitatory and inhibitory neurotransmitters in the RVLM. ExT attenuates hypertension and cardiac hypertrophy partially mediated by attenuating oxidative stress and modulating neurotransmitters in the RVLM

Microbiology, ecology, and application of the nitrite-dependent anaerobic methane oxidation process

Nitrite-dependent anaerobic methane oxidation (n-damo), which couples the anaerobic oxidation of methane to denitrification, is a recently discovered process mediated by “Candidatus Methylomirabilis oxyfera.” M. oxyfera is affiliated with the “NC10” phylum, a phylum having no members in pure culture. Based on the isotopic labeling experiments, it is hypothesized that M. oxyfera has an unusual intra-aerobic pathway for the production of oxygen via the dismutation of nitric oxide into dinitrogen gas and oxygen. In addition, the bacterial species has a unique ultrastructure that is distinct from that of other previously described microorganisms. M. oxyfera-like sequences have been recovered from different natural habitats, suggesting that the n-damo process potentially contributes to global carbon and nitrogen cycles. The n-damo process is a process that can reduce the greenhouse effect, as methane is more effective in heat-trapping than carbon dioxide. The n-damo process, which uses methane instead of organic matter to drive denitrification, is also an economical nitrogen removal process because methane is a relatively inexpensive electron donor. This mini-review summarizes the peculiar microbiology of M. oxyfera and discusses the potential ecological importance and engineering application of the n-damo process

An Epidemiological Study of Drug Resistance and Resistance Genes in Bovine Escherichia coli Isolates in Heilongjiang Province of China

Background: To explore the epidemiology of bovine multidrug-resistant Escherichia coli isolates and resistance genes in Heilongjiang province of China. This study examined the prevalence of genes in bovine E. coli isolates, which confer resistance to antibiotics that are commonly used in the clinic, in regions of Baiquan, Shangzhi, and Songbei of Harbin. The purpose of the study was to investigate the epidemiology of the main resistance genes of bovine E. coli isolates in clinical veterinary medicine, and to provide a theoretical basis for preventing the spread of drug-resistant bacteria, as well as for rational drug use.Materials, Methods & Results: The sensitivity of 105 isolates to 22 antibiotics was determined using the KirbyBauer disk diffusion method, and the distribution of 19 kinds of common drug resistance genes was investigated using Polymerase Chain Reaction. The results showed that the resistance rate to nine antibiotics was over 50%, including rifampin (84.76%), ampicillin (73.58%), tetracycline (69.52%), and sulfisoxazole (59.05%). In total, 105 strains of bovine E. coli presented 21 spectra of drug resistance, including eight strains (7.62%, 8/105) that were resistant to one antibiotic and four strains (3.81%, 4/105) that were resistant to 21 antibiotics. The resistance gene detection results showed that the streptomycin-resistance gene strA was found in 73 isolates, accounting for 69.52% of the isolates, followed by the sulfanilamide-resistance genes sul3/sul2 and the aminoglycoside-resistance gene aphA, which accounted for 57.14%, 51.43%, and 50.48%, respectively, of the isolates.Discussion: This study revealed serious drug resistance of bovine E. coli isolates in some areas of Heilongjiang province. Of 105 E. coli isolates, more than 50% were resistant to the following antibacterial drugs: rifampicin, ampicillin, tetracycline, sulfisoxazole, and cephalothin. The isolates were the most sensitive to amikacin, with a sensitivity of 84.76%, followed by sensitivity to ofloxacin, ciprofloxacin, norfloxacin, cefoxitin, and tobramycin. Drug sensitivity tests showed that the drug resistance spectra of the bovine E. coli isolates was different in different regions, indicating that there were multidrug-resistant bovine E. coli isolates in different regions of Heilongjiang province, and that drug resistance differed among different regions. This may be due to prolonged use or overuse of antibiotics in a particular locality. Additionally, because of different management modes of livestock farms, the application of antimicrobial drugs in some farms may have imposed selective pressure on the intestinal flora including E. coli, resulting in the horizontal transmission of drug resistance among the bacteria. The study found that some strains had a resistance phenotype, but no resistance gene, while some had a resistance gene without expressing a resistance phenotype, which is consistent with relevant reports in the literature. This may be related to the same genotype corresponding to different resistance phenotypes, or different levels of gene expression, or different drug metabolic rates. In our study, some strains with certain drug resistance genes were sensitive to the corresponding drug, which may be due to mutations of drug-resistance genes, the loss of a strains resistance phenotype, or the loss of gene function. These issues require further study. This study revealed serious drug resistance of bovine E. coli isolates in some areas of Heilongjiang province. Of 105 E. coli isolates, more than 50% were resistant to the following antibacterial drugs: rifampicin, ampicillin, tetracycline, sulfisoxazole, and cephalothin. The isolates were the most sensitive to amikacin, with a sensitivity of 84.76%, followed by sensitivity to ofloxacin, ciprofloxacin, norfloxacin, cefoxitin, and tobramycin